For the same cost there are better choices. We designed them back 30 years ago in aircraft, now the building industry took that and ran without understanding the design. It was never meant to surround people in homes, toxic seal, especially air sealed. IAQ has become very controversial due to "built right built tight" mentality without knowing all the facts and risk. Rather than rewrite below is an email I just sent to attorney yesterday,
My homes are entirely different than this area has ever seen and is one of the most energy efficient(all electric & off grid) in the nation. In order to do that I will air seal the home VERY tight. The legal issues are that despite an air ventilation system, sealing in toxic chemicals that are not expelled by air, I do not use is the norm. As a matter of fact, there have been law suits around the country as a result of sealing in "sick homes". I designed the home properly with the IAQ (Indoor air quality tested by third party). I have already started telling my clients if they want to change the design to bring in toxic materials they will have to sign a release of liability.
Another difference in my homes is I have two passive ventilation systems besides the active ERV. The best approach is to not seal in a sick home is don't bring sick materials like PU foams into the building. Sounds simpler than it is, especially for production homes, lack of natural raw materials and trades can drive cost up. Natural materials can cause poor IAQ if they are not processed right.
As soon as we try to create our own weather system the need for greater insulation and plastic sick film becomes nessassary.
Any attempt to seal anything in nature becomes a sick environment for mammals.
My experience is that the next big thing or the next regulation is not the solution, however the earlier methods tend to hold the most usefull solution or the info needed to create one.
Also baffling how many of the better natural building materials we discuss out here are never promoted by the "green" building scientist nor is there much proof, testing, or discussions on IAQ. Wonder why? No sponsors.
I was at a home show lately explaining IAQ and natural materials. The hemp was big draw. Many did know it is a great building material that absorbs CO2 like a plant and gets harder and harder with as high of r-value and far better dynamic hygrothermal mass we have built with for centuries. I explained I am not doing anything new, just bringing back better materials and building practices along with tested and proven IAQ. I told people to go get another builder to provide a third party IAQ, if not call me
Many parts of the country have worse outdoor air quality than indoor. Many do not want to open windows or whole house fans due to allergies, farmers around here that stir up dust. Dusty winds are a big problem in dry desert climates like out west. I think we are moving to a condition air demand with HEPAs, MERVs, etc....
Air sealing makes sense only if done properly.
I was talking to our local fire marshal at a local city meeting late last week about hempcrete he referred to as a "alternate building material" since it is not in international or local codes. Why? Politics and $$$$. I explained the burn rate of rock (limestone slag) and soil is better, lower than what we use today. Imagine that when does rock and soil burn? Saves lives. He was very supportive but may want me to dig up some test info from centuries ago. I also explained I don't use combustible appliances or gas, or fossil fuels, to power my homes. More "alternative building methods" I guess
See that plastic bag of weed I mean hemp on the table I labeled it. Very entertaining! To the right is a hemp casted cube with a lime plaster. To the left of the mineral wood board is a hemp batt. I also have mag board, and was doing water demos on all. I let people smell our eatable food grade mineral silicate paint vs latex that almost knocked them out most builders use. ROMA and Heim are the only to mfgs I know, I have to ship in since quality paint is not available. When I say quality I mean no MVOC, not low VOC sales hype.
The best part was competition and suppliers coming over to learn about what I was doing and hear my presentations to potential clients I had to kick to the curb